Trispectrum estimator in equilateral type non-Gaussian models - High Energy Physics - TheoryReport as inadecuate




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Abstract: We investigate an estimator to measure the primordial trispectrum inequilateral type non-Gaussian models such as k-inflation, single field DBIinflation and multi-field DBI inflation models from Cosmic Microwave BackgroundCMB anisotropies. The shape of the trispectrum whose amplitude is notconstrained by the bispectrum in the context of effective theory of inflationand k-inflation is known to admit a separable form of the estimator for CMBanisotropies. We show that this shape is $87 \%$ correlated with the fullquantum trispectrum in single field DBI inflation, while it is $33 \%$correlated with the one in multi-field DBI inflation when curvatureperturbation is originated from purely entropic contribution. This suggeststhat $g { m NL} ^{equil}$, the amplitude of this particular shape, provides areasonable measure of the non-Gaussianity from the trispectrum in equilateralnon-Gaussian models. We relate model parameters such as the sound speed, $c s$and the transfer coefficient from entropy perturbations to the curvatureperturbation, $T {\mathcal{R} S}$ with $g { m NL} ^{equil}$, which enables usto constrain model parameters in these models once $g { m NL}^{equil}$ ismeasured in WMAP and Planck.



Author: Shuntaro Mizuno, Kazuya Koyama

Source: https://arxiv.org/







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